MIC4680
1A 200kHz SuperSwitcher™
Buck Regulator
General Description
The MIC4680 SuperSwitcher™ is an easy-to-use fixed or
adjustable output voltage step-down (buck) switch-mode
voltage regulator. The 200kHz MIC4680 achieves up to
1.3A of continuous output current over a wide input range
in a 8-pin SOIC.
The MIC4680 is available in 3.3V and 5V fixed output
versions or adjustable output down to 1.25V.
The MIC4680 has an input voltage range of 4V to 34V,
with excellent line, load, and transient response. The
regulator performs cycle-by-cycle current limiting and
thermal shutdown for protection under fault conditions. In
shutdown mode, the regulator draws less than 2µA of
standby current.
The MIC4680 SuperSwitcher™ regulator requires a mini-
mum number of external components and can operate
using a standard series of inductors and capacitors.
Frequency compensation is provided internally for fast
transient response and ease of use.
The MIC4680 is available in the 8-pin SOIC with a
–40°C to +125°C junction temperature range.
Features
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SOIC-8 package with up to 1.3A output current
All surface mount solution
Only 4 external components required
Fixed 200kHz operation
3.3V, 5V, and adjustable output versions
Internally compensated with fast transient response
Wide 4V to 34V operating input voltage range
Less than 2µA typical shutdown-mode current
Up to 90% efficiency
Thermal shutdown
Overcurrent protection
Applications
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Simple 1A high-efficiency step-down (buck) regulator
Replacement of TO-220 and TO-263 designs
Efficient pre-regulator (5V to 2.5V, 12V to 3.3V, etc.)
On-card switching regulators
Positive-to-negative converter (inverting buck-boost)
Simple battery charger
Negative boost converter
Higher output current regulator using external FET
Typical Application
+6V to +34V
C1
15µF
35V
SHUTDOWN
ENABLE
MIC4680-3.3BM
2
IN
SHDN
GND
5–8
SW
FB
3
L1
68µH
3.3V/1A
C2
220µF
16V
1
4
+5V to +34V
C1
15µF
35V
SHUTDOWN
ENABLE
2
MIC4680BM
IN
SW
SHDN
GND
5–8
3
L1
68µH
R1
3.01k
R2
2.94k
2.5V/1A
C2
220µF
16V
1
Power
SOIC-8
D1
B260A or
SS26
FB
4
Power
SOIC-8
D1
B260A or
SS26
Fixed Regulator Circuit
Adjustable Regulator Circuit
SuperSwitcher is a trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 2008
M9999-032808
MICREL [ MICREL SEMICONDUCTOR ]
